Manufacture of rayon



United States Patent MANUFACTURE OF RAYON Pieter Coenraad Limburg, Arnhem, Aart Bnurman, Velp, .and Robbert Aldert Vroom, Arnhem, Netherlands, assignors to American Enka Corporation, Enka, N.C., a corporation of Delaware 7 rayon and more particularly to an improved process for making rayon and to an improved viscose spinning solution.

In Dutch patent application Serial No. 195,721 a process is described for the manufacture of artificial threads, fibers and like products from viscose, in which a viscose solution containing polymers of an epoxyalkane in quan titles of 0.11% by weight (calculated on the viscose) is spun in a sulfuric acid spinning bath. The bath contains at least 2% zinc sulfate and, in percentage by weigh-t, the H 80 content of the bath does not exceed 1.3 times the alkali content 'ofthe viscose. By means of this process threads areobtained which show a so-called skin structure. Consequently the swelling value of these threads is low and the double loop strength as well asthe resistance to abrasion are high. These threads are very suitable for the manufacture of tire cord. Staple fibers similarly made may be especially used in those cases where a satisfactory resistance to washing is required.

In the processing to cord a number of threads are combined and twisted together. It is known that during this process twisting losses occur, i.e; the strength of the manufactured cord is less than the sum of the strengths of the composite threads. These twisting losses will hereinafter be called cord losses.

It has already been previously foundas described in Dutch patent application Serial No. l97,805-that by using epoxyalkane polymer having a specific composition and molecular weight, namely by using polymers of epoxyethane having a molecular weight of between 3800 and 4200, the cord loss may be reduced. 7 7

It has now been found that by using afcombination. of the polymers of the epoxyalkane with certain amines in a specific ratio the. cord loss may be even further reduced. V g

It is an object of this invention to provide a methodfor making rayon yarn having improved physical properties by utilizing a novel combination of modifiers.

Another object isv to provide a new viscose spinning solution. N 1 Other objects will be apparent from the following detailed description.

The presentinvention consists of a process of spinning 7 into" an acid spinbath a viscose solution that contains, in addition to the epoxyalkane polymers, also one or more compounds of the general formula; I (CnH2nO)xH R N (CnH2n )y in which R is an aliphatic chain having at least8 C-atoms,

in which n is 2, 3 or. 4 and x-l-y is at least 2, while neither 7 x nor y may be zero, the quantity of .the substituted amines amounting to 15 to 40% by weight of the total 7 mers which are used in combination with the aboveamounts of the epoxyalkane polymer and the amine.

Patented Apr. 4, 1961 ice are the products marketed under the names of Ethomeen C/15, Ethomeen C/20, Ethomeen C/25, Ethomeen C/ 60, Ethomeen S/ 15, Ethomeen S/20, Ethomeen S/25, Ethomeen S/ 60, Ethomeen T/ 15, Ethomeen T/20, Ethomeen T/25, Ethomeen T/ and Hills V 1011 T.

The Ethomeens are prepared by reactingamines derived from higher fatty acids with ethylene oxide. In

this way the C-Ethomeens are derived from coconut oil,

the S-Ethomeens from soybean oil and the T-Ethomeens from tallow. The numbers 15, 20, 25 and 60 following on the capitals indicate, after a deduction by 10, the number of ethylene oxide molecules which have reacted with 1 molecule of the amine.

Hiils V 1011 T is a representative of the group of compounds of the formula:

(CH2CH20) :H

(omoHzm n in which R represents an alkyl radical having 8 to 24 C-atoms, (x+y) has a value of between 5 and 25 and neither 2; nor y are zero.

If the aforementioned amines together with epoxyalkane polymersrin the stated amounts of 15 to 40% by weight, calculated on the mixture of the epoxyalkane polymers and the amines, are added to viscose, said amines reduce the cord losses which up till now occurred when using only epoxyalkane polymers. It seems that this should be attributed to the fact that these'amines give the threads a smoother surface. When using only the epoxyalkane polymers said surface namely is rather rough. J The smoother surface means that also the dirtadhering capacity. is smaller so that after the threads have been cut to staple they are very suitable to beused moleculariweight' of 3000 it is preferred to use thecommercial product Hiils V 1011 T in an amount of 25% by weight (calculated on'the total weight of the polyepoxyethane and the amine). The epoxyalkane polymentioned nitrogen compounds may be straight polymers, copolymers or so-called block polymers of epoxyalkane or substitution products thereof. The epoxy compounds from which the polymers used are prepared have the general formula: H

ROHCHr in which R represents hydrogen, an alkyl group a cyclo alkyl group or an aryl group. Examples thereof are o epoxyethane and epoxypropane. An example of a block polymer is HO(C H O),,(C H O) (C H O) H, in which b equals 30 and a+c equals ,85. Of these polymersan amount of between 0.20.5% by weight, calculated on the viscose, is in general added to the spinning solution.

With an amount of 0.2% by weight of polyepoxyalkane the amount of the amine lies approximately between 0.04 and 0.11% by weight. If used in unmixed condition these amounts do not give rise to the formation of threads with a skin character. If larger amounts of the epoxyalkane polymer and higher mixing ratios between the amine and the epoxyalkane polymer are used the concentration of the nitrogen compound enters the range where the latter compound itself causes the production of threads with a skin character, but in that case the effect is achieved that in processing the threads to cord, losses become lower than without the use of said nitrogen compounds.

It is preferred to use amounts of the nitrogen-containing substance which lie in the lower percentages of the indicated range. This has the advantage that when regenerating the spinning bath, which is carried out under evaporation, as well as when deaerating viscose before spinning, an inconvenient formation of foam is avoided to a considerable degree.

Although it is possible to operate with spinning baths having a sulfuric acid content of 10% by weight and higher, it has been found preferable, in connection with the properties of the threads, such as the strength and the swelling in water, to operate with spinning baths in which the sulfuric acid content is less than 7% by weight.

The zinc sulfate content in the spinning baths may vary considerably above the minimlm of 2% by weight and may amount for example, to 10% by weight and higher. For economic reasons the lower percentages deserve preference.

The drawing which is necessary to obtain therads having the required properties may be carried out in a socalled one-bath process as well as in a second bath and in one or more stages.

When the drawing operation is carried out in a second bath this is, as usually, arranged so that at the end of the drawing process the cellulose xanthate is decomposed to a considerable degree, preferably to a cellulose xanthate ratio of maximum 0.02.

By the xanthate ratio, which is determined according to the method also known for the determination of the gamma number, is meant the ratio between the number of the xanthate radicals still present and the total number of the glucose radicals (C H O The invention will be further explained with reference to the following examples which are to be regarded by no means as restrictive. In these examples the composition of the viscose, the spinning bath, etc., is expressed in percentages by weight.

Example I culated on the viscose, as well as0.15% polyethylene oxide having a molecular weight of about 4000 and also' 0.05% of the product marketed under the name of Hiils V 1011 T. This solution was spun at a Xanthate ratio of 0.48 and a viscosity of 70 sec. (falling ball test) into an aqueous spinning bath at 46 C. containing 3.2% sulfuric acid, 12.0% sodium sulfate and 6.0% zinc sulfate. In the spinning bath the frshly spun thread was immersed for a distance of 95 cm., passing through a two diameter tube. The first portion of the tube had a length of 55 cm. with a diameter of 20 mm. and the secend portion a length of 30 cm. with a diameter of 30 mm. The thread was drawn 45% in the atmosphere andthen drawn 50% in a second bath containing 3% H SO and less than 2% salts: The temperature of the '4 l second bath was 95 C. The length of immersion in the second bath was 150 cm. The speed at which the thread was then collected on a spool amounted to 62 m./m,ir 1. The thread obtained was thereafter washed free from acid in the usual manner, sized and dried under tension after which th eproperties were determined. The thread, which had a total denier of 1656 and consisted of 1000 filaments, was then found to have a swelling value of 68%. The double loop strength-and the resistance to abrasion were excellent. The cord loss amounted to 16%, whereas without the addition of the nitrogen compound the cord loss amounted to 24%.

Example 11 A viscose having a cellulose content of 7.3% and a sodium hydroxide content of 5.5%, and containing 0.11%

. of polyethylene oxide having a molecular weight of 3000 as well as 0.04% of the substance marketed under the name of Ethomeen C/25, was at a xanthate ratio of 0.45 and a viscosity of sec. (falling ball test) spun through a spinneret having 1000 orifices of 60 microns into a spinning bath at 49 C. containing 5.2% sulfuric acid, 13.0% sodium sulfate, 4.5% Zinc sulfate and 0.05 laurylpyridinium sulfate.

After leaving the spinning bath in which the freshly spun threads passed through a tube of the shape and dimensions stated in Example I and in which the length of immersion was 110 cm., the freshly spun threads were drawn 100% in a second bath having a length of travel of 120 cm. and containing 2.5% sulfuric acid at 95 C.

After the drawing process the threads were collected in a spinning pot at a speed of 60 m./ min. and were thereafter washed, after-treated and dried in the known manner.

The threads thus produced had a swelling value of 67%. On processing to cord the cord loss amounted to 18% whereas under similar conditions but without using Ethomeen C/25 this loss amounted to 26%.

What is claimed is:

1. A method of producing viscose rayon comprising the steps of spinning a viscose solution having incorporated therein 0.11.0% of an epoxyalkane polymer of the class consisting of epoxyethane polymer and epoxypropane polymer of a molecular weight of about 3000 and a compound of the general formula quantity of the substituted amine being 15-40% by weight of the total amount of the epoxy alkane polymer and the amine compound.

2. The process of claim 1 wherein the epoxyalkane polymer is epoxyethane polymer.

3. The process of claim 1 wherein the acid coagulating bath is a sulfuric acid bath containing at least 2% by weight of zinc sulfate.

4. The process of claim 1 wherein the substituted amine compound added hasthe formula in which R is an alkyl radical having 8-30 carbon atoms, x-l-yhas a value between 5 and 25 with neither x nor y being zero.

5. The process of claim 3 wherein the concentration of the sulfuric acid in the cogulating bathis 70% or less. 6. A viscose spinning solution containing 0.11.0% by 5 Weight of a polymer of an epoxyalkane of the class being 15-40% by Weight of the total amount of the consisting of epoxyethane polymer and epoxypropane polymer of an epoxyalkane and the amine compound. polymer of a molecular weight of about 3000 to about 4000 and a compound havingthe general formula References Cited in the file of this Patent (CHHMOLH 5 e UNITED STATES PATENTS Re. 24,486 Mitchell June 10, 1958 H O) H 2,572,217 Thurmond Oct. 23, 1951 y 2,593,466 MacLaurin et a1 Apr. 22, 1952 in which R is an aliphatic chain having at least 8 carbon 10 2,696,423 Dietrich Dec. 7, 1954 atoms, n is 2, 3, or 4, and x+y is at least 2 with neither 2,852,333 CoX et a1. Sept. 16, 1958 x nor 3 being zero, the quantity of the substituted amine 2,852,334 Hollihan et a1. Sept. 16, 1958 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No, 2,978,292

April 4 1961 Pieter Coenraad Limburg et al.,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 33 for "'minimlm" read minimum line 37, for "therads read threads same column 3 line 68 for frshly'i read freshly column 4, line 6 for "th eproperties" read the properties 70% read 7% 5 line 74, for

Signed and sealed this 15th day of August 1961,

SEAL) Attest- ERNEST w, SWIDER DAVID I LADD Arte-sting Officer Commissioner of Patents 

1. A METHOD OF PRODUCING VISCOSE RAYON COMPRISING THE STEPS OF SPINNING A VISCOSE SOLUTION HAVING INCORPORATED THEREIN 0.1-1.0% OF AN EPOXYALKANE POLYMER OF THE CLASS CONSISTING OF EPOXYETHANE POLYMER AND EPOXYPROPANE POLYMER OF A MOLECULAR WEIGHT OF ABOUT 3000 AND A COMPOUND OF THE GENERAL FORMULA 